WASHINGTON — The U.S. Justice Department said on Wednesday it appointed former FBI Director Robert Mueller as special counsel to investigate possible collusion between President Donald Trump’s 2016 campaign team and Russia.

The move followed rising demands for an independent probe of alleged Russian efforts to sway the outcome of November’s presidential election in favor of Trump and against Democrat Hillary Clinton.

Pressure has been building on Trump over the Russia issue since his firing last week of FBI chief James Comey, who had been leading a federal probe into the matter.

U.S. intelligence agencies said earlier this year that Russia interfered in the U.S. election.

“My decision (to appoint a special counsel) is not the finding that crimes have been committed or that any prosecution is warranted. I have made no such determination,” Deputy Attorney General Rod Rosenstein said in a statement.

“I determined that a special counsel is necessary in order for the American people to have full confidence in the outcome,” he said.